The present invention, in some embodiments thereof, relates to musical instruments and, more particularly, but not exclusively, to a string based musical instruments.
String musical instruments are very popular. Guitar, Piano, Harp, Sitar and Violin are all string instruments. The basic physical formulation of the vibration frequency is a function of the length of the string, the materials of the string and the tension of the string. Those parameters impose a major constrain in the design of a string based musical instrument. Furthermore, the fact that the vibration frequency is in opposite linear relation with length dictates the length of the device and the fret board spacing in devices where the string tune is adjusted by changing the length of the vibrating portion of the strings, for example, in guitars and violin.
One known problem of string musical instrument is the need for constant tuning to mach the instrument to musical note standard and to match the frequency relationship between different strings. This is usually done manually by the musician by rotating a screw that changes the tension of the strings.
In the middle of the 20th century with the emerging of electronics many new musical instrument where made by the advantage of electronic circuits. Electronic based musical instruments used a signal synthesizer that is based on accurate time base, usually a quartz crystal, accurate time base eliminates the need for tuning the musical instrument.
Some musical instrument like organ and piano, that where played by keyboards, where replaced quit well by keyboard synthesizers that sufficiently mimic the sound generated by their counterpart analog musical instrument. Other instruments, especially string instrument where the strings are directly activated by the player fingers, like guitar or harp or by a bow and fingers like violin where not been replaced or mimicked adequately by their electronic synthesized instrument counterpart. The main reason for that is the richness of the sound produced by those instrument that where insufficient mimicked by the synthesizers.
The electric guitar which is one of the most popular instrument in modern music is actually did not change since its initial development in the early years of the 20th century. The actual guitar structure is similar to a classic guitar while the electronic part is only pickup the vibration signal, amplify it and do some sound effect on it like distortion or modulating the original signal. The tuning problem is addressed today mostly by a stand alone tuner instruments. U.S. Pat. No. 3,881,389 filed on May 21, 1973, teaches an early electronic version of such tuner. Digital versions using digital signal processing and digital display are common and well known in the art.
Guitars that are integrating the tuner with motor drivers and adjust the string tension automatically are known as “Robot guitars” and are also start to be offered in recent years. U.S. Pat. No. 5,767,429 filed on Nov. 9, 1995, U.S. Pat. No. 6,184,452 filed on Dec. 19, 1997, and U.S. Pat. No. 7,786,373 filed on Jan. 19, 2005 are example for patents that teach such solutions.
From a different direction there is on going effort to deliver a new guitars-like musical instrument that are based on pure synthesized audio signal. Those devices known as guitar synthesizers are actually similar to keyboard synthesizer that held like a guitar and enable playing the notes similar, more or less, to playing a guitar.
Many guitar synthesizers were suggested and developed. In early days finger location on the fret board was captured by press buttons. In more modern design the fret board is a touch sensitive surface. The strings in those guitar synthesizers are used only to pick the time and the strength of the pluck and the string vibrations generally are not used to synthesize the sound signal. Harmonics, palm mutes, hammer-ons (in which the fretting hand strikes the string onto the fret board), pull-offs, and pick slides are known guitar playing techniques that are not easily produced by guitar synthesizers. Usually, the strings lay only on the guitar body and not on the fret board. In some cases the string are replaced with “virtual strings”—an alternative way to pick the string pluck time. Those virtual strings can be mechanical buttons, laser light beams, touch surface, etc. An example of guitar synthesizer related patents are U.S. Pat. No. 8,003,877 filed on Sep. 26, 2008, U.S. patent application Ser. No. 12/115,519 filed on May 5, 2008, and U.S. patent application Ser. No. 11/731,449 filed on Mar. 30, 2007.